This past weekend at about midnight on March 29, 1848; Niagara residents accustomed to the flow of the river were awakened when the Niagara River ceased to flow. The reason-a strong south-west gale had pushed the ice fields in Lake Erie in motion. Millions of tons of ice became lodged at the source of the mouth of the Niagara River, blocking the channel completely stopping the flow of water over the American and Canadian Horseshoe Falls. The self-made dam held the water for approximately thirty hours until the wind shifted and the pent-up weight of the water broke through to its accustomed route. Niagarans went back to sleep.
Also the American Falls was stopped flowing intentionally from June 1969 until November 1969,when the U.S. Army Corp of Engineers coffer-dammed the Falls to study what actions, if any should be taken to remove the rock debris at the base. It was decided to let nature take its course and to do nothing about the rock renewal.
Attached is a photo of the face of the De-Watered American Falls.